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  • Writer's pictureLilla Schottner

Hydroponics, Soilless Growing

Updated: Nov 1, 2022

I have been working with a hydroponic system at the University of the District of Columbia for the past year, and the more I learn about it, the more I love it. I am fascinated to see how plants grow and develop so fast in the greenhouse setting. We produce all kinds of fruits and vegetables and donate most of them to DC Central Kitchen and the university’s student food pantry. I am happy to contribute with my work, so these communities receive fresh, organic, and nutritious food weekly.

What is Hydroponics? It is a sustainable urban farming technology, where plants grow soilless in a greenhouse. Their roots hang in water with a rich mix of nutrients. (Please find the essential nutrients below) This farming technology provides urban dwellers to grow and produce fresh, nutritious food year-round.

This technique has been practiced for centuries, starting with the Hanging Gardens of Babylon and the Floating Gardens of the Aztecs.

Advantages of a Hydroponic system.

Many crops can grow where the soil is unsuitable, such as in deserts, or soil is contaminated, such as in cities. Because climate change and population growth, this is a significant factor.

Future generations will also face water scarcity; therefore, conserving water and nutrients in the hydroponic system is also a great advantage. The hydroponic system recirculates the water. There is also more control over the environment, temperature, nutrient feeding, and diseases can be eradicated much faster. The growth rate and yields are 30-50 % higher.

Sustainability benefits are: no need for pesticides, reduced transport miles, and an overall reduction of the environmental footprint of crop production.

Disadvantages: high construction and energy costs. Plants' reaction to nutrition is fast, and diseases can spread quickly; therefore, trained personnel must monitor the system daily.

On the left picture: I harvested over 14lbs of cucumbers on July 6th, 2020.

What plants need to grow?

Plants' basic needs are air, light, water, nutrients, and a growing medium. Plants also need essential elements, macro - and micronutrients, to live, grow, and reproduce. Macronutrients are needed in large amounts, and their purpose is as follows:

- Nitrogen is the primary nutrient, and it allows for strong growth of the plant, healthy leaf color, and photosynthesis.

- Phosphorus promotes root development, ripens fruits, it can increase transplant heights and stem diameter. Phosphorus deficiency can cause purple leaves, stems, and stunted plants.

- Potassium promotes overall health and helps to withstand diseases.

- Calcium promotes growth and helps build cell walls.

- Magnesium aids seed formation and regulates the uptake of other nutrients.

- Sulfur maintains the dark green color needed to make chlorophyll.

Micronutrients are those that the plants need in minor or trace amounts.

- Boron regulates plant metabolism.

- Chlorine is for photosynthesis.

- Copper helps plants to metabolize nitrogen.

- Iron and Nickel assist in biochemical processes.

- Manganese assists in chlorophyll production.

- Molybdenum helps the plant to use nitrogen.

- Zinc helps the development of enzymes and hormones to form seeds.

Too much or too little nutrients can cause problems or can be toxic to plants.

In conclusion: Hydroponic and aquaponic systems are excellent solutions for growing food in an urban environment, but we must go beyond.

Combining urban and peri-urban and precision agriculture, climate-smart agriculture, conservation agriculture, and the ten principles of agroecology, we can succeed in adapting and building resilient communities while diminishing food insecurity.

On the pictures: Nutrient film technique system, Dutch bucket system from the University of the District of Columbia (UDC) at the Van Ness campus, and Firebird Farm.

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